Cancer typically progresses through a series of phases or stages, and prostate cancer is no exception. It’s important for men to understand what constitutes each of the four stages of prostate cancer so they can better appreciate their treatment options and prognosis.
The four stages of prostate cancer are indications of how far the cancer has spread from the prostate, if at all. The four stages are listed here.
Stage I: The cancer is confined to the prostate, cannot be found through a digital rectal exam (DRE) or scanning, and has a low Gleason score. The Gleason score is based on how the prostate cancer cells are arranged in the gland. Cells that look healthy are assigned a lower score while that that look less like healthy cells or seem to be more aggressive get a higher score. Scoring begins with 6, which indicates low-grade cancer, and goes up to 10, which is aggressive, high-grade cancer.
Stage II: The cancer is still confined to the prostate and cannot be seen or felt during DRE, but it is more advanced and has a higher Gleason score. Stage II prostate cancer is actually divided into two segments: IIa, which means the cancerous cells are confined to one lobe of the prostate, the PSA score is less than 10, and the Gleason score is 6; and IIb, in which cancer cells are identified in both lobes, or cancer cells are in one lobe and the PSA score is 20 or higher, and the Gleason score is 8 or higher.
Stage III: The cancer has spread beyond the prostate into local tissues. It may also have spread to the seminal vesicles.
Stage IV: The cancer has spread to the lymph nodes, bones, lungs, or other sites or organs in the body. Compared with the other three stages of prostate cancer, for which the five-year survival rate is nearly 100 percent, the rate is 29 percent for stage IV.
Read more in our Prostate Cancer Health Center.